Call of the Cape: After weeks spent attuned to every nuance of the empty ocean, the bustle of Cape Town harbour is unreal to Theo Dorgan as he reaches journey's end

I open my eyes and through the hatch overhead I see blue sky streaked with orange. There's a stillness in the air, a murmur of voices from the cockpit. The boat rocks gently fore and aft, a slow steady motion, quite unlike anything we've experienced in the past five weeks. We're there, I think, or nearly. Cape Town, after all this time, all these many many miles.

I dress on a flat floor for the first time in weeks: sea-boots, jeans, my lucky blue corduroy shirt. No thermals, no fleece, no foul-weather gear. I knot Paula's blue scarf around my neck and go up into a crowded silence. The sea is a flat calm, a soft oily roll to it, sheen of milk over the grey-blue lift of it, an occasional lazy white roll coming back from the bow. I see the great black bulk of Table Mountain dead ahead.

First glimpse of Africa from the sea. And it still isn't real, I still can't take it in. The sea mist is rolling back, a tanker passes, stately, going away to the north of us. From time to time somebody murmurs something, but it makes little impression. I keep wanting to say, we're here, Cape Town, journey's end, but some reluctance has a hold of me.

The spell. An unwillingness, even this close in, to make any assumptions.

Coming up, by indelible force of habit, I'd glanced at the plotter, the chart, the clock. I knew before setting foot on deck that we were 10 miles out, but I still won't assent to it.After all this time, all those vicissitudes of weather, course changes and sail changes, day after day turning out so different from what we might reasonably have expected, I believe only in what I know to be the case. You might, I tell myself, be dreaming. I look around me, the whole crew on deck by now, and we're all in the same state of suspension.

Suddenly Simon pecks at the keypad of his phone and I realise he has a signal. He's gone forward now, rapt in conversation and, as simply as that, we are all freed from the spell.

Now it's all bustle: warps and fenders coming up out of the forepeak, Steve on the radio to the harbourmaster for berthing instructions, the mainsail coming down for the last time, flaked into a neat harbour stow. Everyone's busy, quiet and purposeful. I go down for the tricolour in my kitbag, a sentimental gesture, and run it up to the portside spreader. The second ocean it's crossed. Then everything clears, the last of the mist rolls away and we are facing in to the harbour under that stark, sheer extraordinary wall of rock.

We coast in past a new gas exploration platform the size of a New York city block. A few small yachts go by, heading out for the day, their crews incurious. Battered workboats are buzzing this way and that way, a tug crosses behind us, everything normal under a sun that is already hot - and all this is slightly bewildering. We feel, what? Lost? In a way. The ocean behind us is vast, cold and empty. Discounting those brief, dreamlike hours in Tristan da Cunha (I am prepared to be told we were never there at all), we have been 23 days at sea since leaving Stanley.

The world has long since fallen away: the real for us, for so long now, has been the great ocean, our boat ploughing steadily across it. We are so perfectly attuned to every wind-shift, to every rise and fall of the barometer, above all else to the howl of the wind in the rigging, the rise and twist and sudden fall of the deck beneath our feet, that still water, a gliding boat, the hammer and clamour of drills, cranes, trains and traffic on the motorway behind the oncoming marina seems beyond unreal.

Steve, for the last time, stands at the wheel, spins us expertly this way and that, lining us up for our berth. Simon and Fed jump ashore to take the bow lines and then, like that, matter of fact as you like, the fenders kiss the portside pontoon and we are in.

I close my eyes and, one more time, I call up that moment when we plunged through our own bow-wave, in under the great rainbow at Cathedral Rocks, and put the helm hard down to round the Horn. That was us, I think to myself, that was us, we did that. A long, long time ago.

And this is now. Like that. The world again. Somehow, in all the sudden bustle, the port watch is together on the after-deck. Such stalwart companions, Justin, Tony and Kevin. Coffees in hand, we salute each other; nothing needs to be said.

I dig the phone out of my pocket, dial the number for home and turn away. Paula answers, soft joy in her voice.

"We're in," I say. "Cape Town. We're in. I'm coming home."

• Series concluded